Code signals (e.g., Global Positioning System (GPS) signals) use different codes modulated on a carrier signal to increase the information throughput. Various code combining schemes utilizing code signals have been suggested that are easily implemented using a digital waveform generator (DWG), which typically operates at a fixed optimized output back-off level regardless of the code set. To accommodate reconfiguration due to adding or subtracting codes or boosting relative code powers, the gain following the DWG must be adjusted in concert with the redistribution of the code powers in the DWG. As such, the gain following the DWG needs to be adjusted when there is a change in code powers.
Existing solutions use an analog means of waveform generation and are limited to a small set of preselected code configurations. Digital waveform generation allows for an arbitrary combination of codes and code powers. The power range of a combined code set may exceed, for example with a GPS satellite, twenty-three (23) decibels (dB), or greater, as in the case of a single code versus five codes with a boost. However, the DWG is typically operated at an optimal back-off value with a corresponding fixed output power regardless of the code set. The primary reason for this mode of operation is the need to maintain the performance margin above the absolute quantization noise floor and the spurious product of the numerically controlled oscillator (NCO) design. Therefore, it becomes necessary to relegate the requisite gain adjustment to the amplification chain that follows the DWG. It may be possible to pre-compute and store a set of gain adjustment values on-board the vehicle; however, this method detracts from the inherent flexibility of the DWG, unless the table is large and unwieldy. As such, there is a need for improved power adjustment for code signals.